Device and method for clot engagement

ABSTRACT

A clot removal device may include a tubular clot capture element having a first internal diameter and a clot engaging element having a second external diameter. The first diameter and the second diameter may be selected to permit the clot engaging element to be rotated within the tubular clot capture element. A method of removing a clot from a blood vessel may including delivering the tubular clot capture element and clot engaging element to a clot site such that the clot engaging element may rotate within the tubular clot engaging element.

CROSS-REFERENCE TO RELATED APPLICATION

This patent application is a continuation-in-part of U.S. patentapplication Ser. No. 13/059,319, filed on Feb. 16, 2011, entitledEMBOLECTOMY DEVICE, which is a 35 U.S.C. §371 of PCT/IL09/00834, filedon Aug. 30, 2009, which claims the benefits of priority under 35 U.S.C.§§119-120 to U.S. Provisional Application 61/119,369, filed on Dec. 2,2008, and to U.S. Provisional Application 61/093,173, filed on Aug. 29,2008, the entire disclosure of which is incorporated herein byreference.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to devices andmethods for treating occlusions within vasculature. More particularly,embodiments of the present disclosure relate to devices and methods forremoval of clots (e.g., emboli and thrombi) found in blood vessels,among other things.

TECHNICAL BACKGROUND

Blood clots (e.g., emboli and thrombi) are examples of blockages thatmay form in mammalian blood vessels. A clot in an individual's bloodvessel may become dangerous when it restricts blood flow, therebyplacing the individual at risk for medical traumas, such as a stroke ora heart attack. Therefore, there may be a need to remove clots that arelodged within blood vessels.

A variety of devices and procedures have been used to remove clots fromblood vessels. For example, a catheter with a balloon on its distal tipmay be inserted into a blood vessel and passed through the clot, afterwhich the balloon is inflated. The balloon may then be withdrawn fromthe blood vessel to remove the clot.

Another example of a clot removal device is a catheter containing aspiral section at its distal end. The catheter with spiral section maybe delivered to a clot site within a blood vessel, and the spiralsection may then be used to cut into the clot. The spiral section,therefore, may grasp to an inner portion of the clot prior towithdrawing the clot from the blood vessel.

One risk that exists with clot removal devices is that a piece of theclot may break away during the removal process, travel through thevasculature, and cause traumatic damage. This may occur for variousreasons. For example, if the clot removal device passes through the clotprior to deployment, the pre-deployment activity can disrupt the clot,causing pieces to break away. Further, there is an increased risk ofdeploying a device in uninvolved distal territory. There is a need fordevices and methods that may allow a clot to be removed from a bloodvessel, while reducing the risk that a clot or portion of a clot maybecome dislodged during the removal process, causing further risk to thepatient.

SUMMARY OF A FEW EXEMPLARY EMBODIMENTS

Embodiments of the present disclosure provide devices and methods forremoving clots from blood vessels.

An aspect of the present disclosure may include a clot removal devicewith a tubular clot capture element having a first internal diameter anda clot engaging element having a second external diameter. The firstdiameter and the second diameter may be selected to permit the clotengaging element to be rotated within the tubular clot capture element.

In various embodiments, the clot removal device may include one or moreof the following features alone or in combination: the tubular clotcapture element may include a mesh-like structure; the clot engagingelement may include a coil; the first diameter and the second diametermay be chosen such that an outer surface area of the clot engagingelement contacts an inner surface area of the clot capture element; alocking mechanism may lock the clot engaging element within the clotcapture element; the first diameter and the second diameter may beselected to permit the clot engaging element to longitudinal move withinclot capture element; the first diameter and the second diameter may beselected to permit the clot engaging element to expand within the clotcapture element; and a control shaft may extend from a proximal end ofclot capture element, and a shaft may extend from a proximal end of clotengaging element, and wherein the shaft may be configured to rotatewithin the control shaft.

In another aspect, a method of removing a clot from a blood vessel mayinclude delivering a tubular clot capture element having a firstdiameter to a clot site, delivering a clot engaging element having asecond external diameter to the clot site, wherein the first diameterand the second diameter may be selected to such that the clot engagingelement rotates within the tubular clot capture element. The clotengagement element may expand or longitudinally move with the tubularcolt capture element. Additionally, a shaft extending from a proximalend of the clot engaging element may rotate within a control shaftextending from a proximal end of the clot capture element.

Additional aspects of the disclosure will be set forth in part in thedescription which follows, and in part will be readily ascertainablefrom the description, or may be learned by practice of the disclosure.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the invention, as claimed.

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate several embodiments of thedisclosure and together with the description, serve to explain theprinciples of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a sectional view of a medical device for removing a clot froma blood vessel, consistent with an embodiment of the disclosure.

FIGS. 1B and 1C are a sectional views of a the medical device of FIG. 1Ain expanded configurations.

FIG. 2 is a perspective view of a clot capture element and clotengagement element of the medical device of FIG. 1A.

FIGS. 3A-3B are perspective views of a clot capture element, consistentwith a second embodiment of the disclosure, in contracted and expandedconfigurations, respectively.

FIGS. 4A-4B are perspective views of a clot capture elements, consistentwith third and fourth embodiments of the disclosure, respectively.

FIG. 5 is a perspective view of a conventional locking mechanism for usewith the medical device of FIG. 1A.

FIG. 6A-6B are sectional views of a body portion showing steps of amethod of removing a clot from the body portion, using the medicaldevice of FIG. 1A.

FIGS. 7A-7B are sectional views of the body portion of FIGS. 6A-6Bshowing movement of a clot engagement element during a method ofremoving a clot from the body portion, using the medical device of FIG.1A.

FIGS. 7C-7D are sectional views of the body portion of FIGS. 6A-6Bshowing steps of removing a clot from the body portion, using themedical device of FIG. 1A.

FIG. 8 is a sectional view of the body portion of FIGS. 6A-6B showingforces acting on a clot during a method of removing the clot from thebody portion, using the medical device of FIG. 1A.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to exemplary embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

Embodiments of the present disclosure relate generally to medicaldevices and methods for treating occlusions in a body. Moreparticularly, embodiments of the present disclosure relate to devicesand method for removing clots, including, but not limited to, emboli andthrombi from blood vessels. It should be emphasized, however, thatembodiments of the present disclosure may also be utilized in othermedical procedures where removal of a blockage or a foreign body isdesired.

In accordance with embodiments of the disclosure, there may be provideda clot removal device including an expandable clot engagement element.An expandable clot engagement element may be any structure that, upondeployment in a blood vessel, may be able to grip, grasp, circumscribe,or retain and/or retrieve a blood clot or other obstruction.

FIG. 1A illustrates one example of a clot engagement element 102, inconnection with exemplary clot removal device 100. For purposes of thisdisclosure, “proximal” refers to the end closer to the device operatorduring use, and “distal” refers to the end further from the deviceoperator during use.

As illustrated in FIG. 1B, in one embodiment, clot engagement element102 may include a coil with one or more windings 108. The windings 108may be angled relative to a longitudinal axis 1006 of a blood vessel1002 (FIG. 7A). The angle of the windings 108 may range fromapproximately 0 degrees to approximately 180 degrees, and morepreferably from approximately 90 degrees to approximately 180 degrees.

A plurality of windings 108 may further form a helical configuration,whereby the plurality of windings 108 share a substantially constantpitch P and/or a substantially constant radius R, as illustrated withreference lines in FIG. 7A. Thus, during rotation, adjacent windingshaving the same radius and pitch will follow substantially the same pathof rotation. Alternatively, the one or more windings 108 may includes avaried pitch and/or a varied radius. The one or more windings 108 may beany shape and/or configuration such that they may be configured torotate about a clot lodged within a blood vessel, to grasp at least aportion of the outer circumference of the clot, and to separate the clotfrom the blood vessel (FIG. 6B). For example, the one or more windings108 may be wound in any suitable shape, including, but not limited to acircle and an oval. The one or more windings 108 may also be acontinuous piece of material. The continuous piece of material may haveany suitable cross-sectional shape, including, but not limited to, acircle, an oval, a ploygon, or any other shape that is capable of beingwound.

The one or more windings 108 may further include an atraumatic bottom,clot contacting surface that may be substantially flat or rounded. Thebottom, clot contacting surface of the one or more windings 108 maymitigate the tendency of a clot 1000 to break into multiple pieces uponcontact. Further, the bottom, clot contacting surface of the one or morewindings 108 may be textured for enhanced gripping of a clot 1000. Atop, exterior surface of the one or more windings 108 may also be anatraumatic surface. The atraumatic top, exterior surface of the one ormore windings 108 may mitigate damage to tissue that the one or morewindings 108 may contact at a clot site. Windings 108 may also include acoating on their top and/or bottom surfaces. The coating may include,but is not limited to, a lubricant and/or an anesthetic.

Clot engagement element 102 may further be a spring-like memberconfigured to self-expand and retract. Expansion and retraction may bein longitudinal and/or radial directions. Accordingly, clot engagementelement 102 may include a contracted configuration (FIG. 1A) and anexpanded configuration (FIG. 1B). The contracted configuration may bemaintained when a sheath 118 substantially surrounds an outer surface ofclot engagement element 102. The expanded configuration may be achievedwhen sheath 118 is removed from at least a portion of the outer surfaceof clot engagement element 102 (Sheath 118 will be discussed in furtherdetail below).

Clot engagement element 102 may be configured to expand to approximatelyan inner diameter of a blood vessel 1002 (FIG. 7A). Expansion toapproximately an inner diameter of blood vessel 1002 may result (but notnecessarily result) in clot engagement element 102 exerting a force on awall 1004 of blood vessel 1002. If a force is exerted on the vessel wall1004, the force may result in separation of a clot 1000 from wall 1004of blood vessel 1002. The resulting separation may be beneficial becausein many instances, clot 1000 may be lodged in blood vessel 1002.Accordingly, separation of clot 1000 from wall 1004 of blood vessel mayreduce the amount of force required to further remove clot 1000 fromblood vessel 1002 and mitigate the tendency of clot 1000 to break intomultiple fragments during removal from blood vessel 1002.

A shaft 116 may extend from a proximal end of clot engagement element102. Shaft 116 may be an elongate member configured to controlrotational and longitudinal movement of clot engagement element 102. Forexample, as illustrated in FIG. 7A, movement of shaft 116 in thedirections shown by arrow 1010 may cause movement of clot engagementelement 102 in the directions of arrow 1010′. Further, rotation of shaft116 in the direction of arrow 1012 may cause rotational movement of clotengagement element 102 in the direction of arrow 1012′.

Shaft 116 may have any shape and/or configuration so long as shaft 116may be configured to rotate and advance clot engaging element 102.Further, shaft 116 may have any suitable cross-sectional shape so longas shaft 116 may be configured to rotate. (FIG. 7A).

While the foregoing described embodiment presents an example of clotengagement element 102 as a wound structure, in a broader sense, theclot engagement element may have any shape and/or configuration so longas it is capable of grasping and removing a clot from a blood vessel.Further, the clot engagement element may be any size such that it iscapable of traversing a lumen of a blood vessel.

The clot engagement element may be constructed of any suitablebiocompatible material having sufficient flexibility and/or rigidity totraverse the lumen of the blood vessel. Biocompatible materials mayinclude, but are not limited to, synthetic plastics, stainless steel,ePTFE, PTFE, metal-polymer composites, and metal alloys of nickel,titanium, nickel-titanium, copper cobalt, chromium, and iron.

In broader embodiments of the disclosure, a clot engagement element mayinclude any structure or mechanism capable of engaging with a clot orother obstruction. For example, a clot engaging element may include oneor more hooks, forceps, expandable cages, expandable balloons, orthermal or chemical mechanisms for causing a mechanical structure toconnect with a clot or obstruction.

In accordance with at least some embodiments of the disclosure, theremay be provided an expandable clot capture element. An expandable clotengagement element may be any structure that, upon deployment in a bloodvessel, is able to capture a clot that has been engaged by a clotengaging element.

Consistent with an exemplary embodiment of the disclosure, an exemplaryclot capture element 104 is illustrated in FIG. 1. The clot captureelement 104 may be constructed to enable clot engagement element 102 tobe movable therein upon deployment in a blood vessel. For example, uponremoval of sheath 118 as will be described later in greater detail, clotengagement element 102 may be configured to rotate, expand, and/orlongitudinally slide within clot capture element 104.

As illustrated in FIG. 1C, clot capture element 104 may include, but isnot limited to, a catheter having a proximal end 104 a and a distal end104 b. Proximal and distal ends 104 a, 104 b may each include an openingtherein 112. Opening 112 at proximal and distal ends 104 a, 104 b may bein communication with a central lumen 110 in clot capture element 104(FIG. 1A). Central lumen 110 in clot capture element 104 may allow forinsertion of clot engagement element 102, as well as other componentsthat may aid in a medical procedure, including, but not limited to, anoptional guidewire 120, vacuum source, illumination and/or imaginingdevices, and tools for grasping a clot.

Clot capture element 104 may further be configured to expand andcontract. Accordingly, clot capture element 104 may be configured totransition between a contracted configuration (FIG. 1A) and an expandedconfiguration (FIG. 1B), in a spring-like manner, in response tomovement relative to a surrounding sheath 118. Similar to clotengagement element 102, clot capture element 104 may be configured toexpand to a size that is substantially the same as an inner diameter ofblood vessel 1002 at a clot site. The expansion of clot capture element104 to the inner diameter of blood vessel 1002 and exerted force onblood vessel wall 1004 at the clot site may aid in separating a clot1000 from a wall 1004 of blood vessel 1002. The separation may result ina reduction of the required force to remove clot 1000 from blood vessel1002. The separation may also aid in mitigating the tendency of clot1000 to break into multiple pieces during removal of clot 1000 fromblood vessel 1002.

Clot capture element 104 may be any shape and/or configuration such thatit may traverse a lumen of a blood vessel. In one embodiment, clotcapture element 104 may be a hollow tube having a constant diameter.Alternatively, clot capture element 104 may have a diameter that variesalong its length. For example, as illustrated in FIG. 2, clot captureelement 104 may have a diameter that tapers at proximal end 104 a, suchthat proximal end 104 a may be configured to connect to a distal end ofa control shaft 114 (Control shaft 114 will be discussed in furtherdetail below).

Clot capture element 104 may be constructed of any known, suitablebiocompatible material having sufficient flexibility and/or rigidity totraverse the lumen of the blood vessel. Biocompatible material of clotcapture element 104 may further include properties that may enable clotcapture element 104 to expand and contract in the manner previouslydiscussed. Accordingly, biocompatible materials may include, but are notlimited to, synthetic plastics, silicone elastomers, thermoplasticelastomers, nickel-titanium, stainless steel, ePTFE, PTFE, polyimides,polyamides, HDPE, polypropylene, polyvinylchloride, LDPE, metal-polymercomposites, and metal alloys.

Clot capture element 104 may include a single biocompatible material ora combination of multiple biocompatible materials. In one embodiment,clot capture element 104 may include a variety of biocompatiblematerials, such that the type and properties of the biocompatiblematerial may vary dependent on the location of the biocompatiblematerial on clot capture element 104. For example, distal end 104 b ofclot capture element 104 may include materials having spring-likeproperties. Such biocompatible materials may include, but are notlimited to, polyurethanes, low density polyethylene, polyvinylchloride,Nitinol and THV.

It may be desired to have proximal end 104 a of clot capture element 104include a stiffer biocompatible material than that of distal end 104 b.The biocompatible material of proximal end 104 a of clot capture element104 may be any suitable degree of stiffness, so long as clot captureelement 104 may be configured to traverse a lumen of a blood vessel.Accordingly, the biocompatible materials of proximal end 104 a of clotcapture element 104 may include, but are not limited to, polyimides,polyamides, high density polyethylene, polypropylene, polyvinylchloride,PTFE, polysulfones, copolymers and blends or mixtures of theaforementioned materials.

Clot capture element 104 may be a unitary structure, formed of acontinuous piece of material. Alternatively, as illustrated in FIG. 2,clot capture element 104 may include a multiple components 106. In oneembodiment, for example, the multiple components 106 may include aplurality of woven braids intertwined to form a mesh-like structure(FIG. 2). The plurality of woven braids 106 may be connected to oneanother via any known means. Alternatively, the mesh-like structure maybe in the form of a net, and the plurality of woven braids 106 may crossone another without being connected, whereby the plurality of wovenbraids 106 may be configured to move relative to one another.Additionally, the plurality of woven braids 106 may include a pluralityof wires. The wires may be crossed and bent to form the mesh-likestructure in a manner such that proximal and distal ends 104 a, 104 b ofclot capture element 104 may be free of open ends of wires (FIG. 2). Anabsence of open ends may result in reduced trauma to the blood vessel.In other embodiments, free open ends may be used. In some of thoseembodiments, the open ends may be bent slightly inward or may beotherwise physically structure to minimize vessel trauma.

When a mesh-like structure is employed in the clot capture element 104,the mesh can be constructed in a manner similar to a Chinese fingertrap, such that longitudinal retraction forces cause the cylindricalstructure to contract radially.

Thus, regardless of other structure that may be employed, one embodimentof the disclosure may simply include a tubular clot capture element,wherein the clot capture element is configured for deployment in a bloodvessel for surrounding a clot, the clot capture element having anopening therein configured to receive and guide a clot engaging element,the clot capture element being configured to radially contract uponretraction, such that when the clot capture element surrounds a clot andis retracted in a longitudinal direction of the blood vessel, the clotcapture element is configured to exert a radially inward compressionforce on the clot.

Thus, for example, one embodiment of the disclosure may simply be thestructure of capture element 104 in FIG. 2, which has a tubular shapeformed of a mesh 106 with an opening 112 at proximal end 104 a forreceiving and guiding a shaft 116. As the result of its mesh-likestructure, upon retraction, the capture element 104 contracts radiallyinward.

The mesh-like structure can be a net or it can be braided. The netitself might include a plurality of crossing braids such that thecrossing braids are movable relative to each other. The net mightinclude a plurality of wires where one or more of the proximal anddistal ends of the capture element are free of open ends of wires (see,e.g., distal end of capture element 104 in FIG. 2, where the there areno exposed free ends of wires.).

FIGS. 3A-3B and 4A-4B illustrate alternatives to the mesh-likestructure, which may include any suitable self-expanding structure. Forexample, suitable self-expanding structures may include, but are notlimited to, rounded coils, flat ribbon coils, a plurality of expandablerings (FIGS. 3A-3B), and/or stent-like structures (FIG. 4A-4B).Self-expanding structures may further be supported between multiplelayers of material 306 (e.g., polymers) which may provide suitablestructure to clot capture element 104.

Clot capture element 104 may further include an atraumatic exteriorsurface that may limit tissue damage upon deployment at a clot site.Clot capture element 104 may also include a coating on its exteriorand/or interior surfaces. The coating may include an anesthetic and/or alubricant, which may aid in deployment of clot capture element 104 andclot engagement element 102 and/or may aid in movement of clotengagement element 102 within clot capture element 104.

As noted above, proximal end 104 a of clot capture element 104 may beconnected to control shaft 114. (See, e.g., FIG. 2) Control shaft 114may be an elongate member configured to pull clot capture element 104into the contracted configuration. Elongate member of control shaft 114may be a hollow tube with a solid wall construction, a braided wallconstruction, a wound wall construction, a hypo-tube (i.e., solid wallconstruction with portions removed to facilitate flexing. The hollowtube may have openings on each end such that control shaft 114 may be incommunication with central lumen 110 (FIG. 1) of clot capture element104. Control shaft 114 may thereby allow for passage of tools,including, but not limited to a guidewire 120, and instrumentation forengaging with a clot 1000. Control shaft 114 may further allow forpassage of shaft 116 of clot engagement element 102, as illustrated, forexample in FIG. 2. Alternatively, control shaft 114 may be of solidconstruction, and shaft 116 may be positioned adjacent shaft 114, asopposed to running through it.

Shaft 116 may have a diameter that is less than a diameter of controlshaft 114, which may allow for clot engagement element 102 to move alonga longitudinal axis of clot capture element 104. Shaft 116 may alsoinclude a friction minimizing exterior surface. For example, theexterior surface of shaft 116 may be smooth and/or may include alubricious coating such that shaft 116 may slide with relative easewithin control shaft 114. Shaft 116 may further include a lumen therein.The lumen may be in communication with clot capture element 104. Thelumen may also be in communication with a lumen 1008 in a blood vessel1002 when clot removal device 100 is delivered to a clot site.Accordingly, the lumen may allow for insertion of tools useful during aclot removal procedure, including, but not limited to, a guide wire 120,a suction device, illumination devices, imaging devices, and/or suitableinstrumentation for grasping a clot.

Control shaft 114 may include a diameter sized to receive shaft 116 inorder to allow clot engagement element 102 to be moved within clotcapture element 104 through movement of shaft 116. Shaft 116 may have alength that is longer than a length of control shaft 114 (FIG. 2) suchthat control shaft 114 may at least partially surround shaft 116, whichmay allow for a device operator to control longitudinal and rotationalmovement of clot engagement element 102. Control shaft 114 may furtherbe configured to maintain a portion of shaft 116 of clot engagementelement 102 in a non-contacting relationship with blood vessel wall 1004and may be configured to maintain clot engagement element 102 in adesired position relative to clot 1000 at a clot site. Accordingly,control shaft 114 may act as a stabilizer for clot engagement element102 when clot engagement element 102 is within clot capture element 104.For example, the diameter of control shaft 114 may be large enough toallow for longitudinal and rotational movement of shaft 116, but smallenough to prevent shaft 116, and thereby clot engagement element 102,from substantially deviating from a predetermined location relative toclot 1000. Thus, a second shaft (shaft 116) is rotatable and/or movablewithin a first shaft (control shaft 114). One function of control shaft114 may be to center shaft 116 within the vessel, such that whenengagement element 102 is rotated, the rotation occurs in asubstantially longitudinal direction of the vessel.

In the absence of control shaft 114, or in addition to it, centering ofthe engagement element within the vessel can occur as the result of atapering of capture element 104, or through the use of a spacer, notshown, for centering shaft 116 in the vessel. In this regard, anotherembodiment of the disclosure may include a clot removal device, having ashaft, a clot engagement element on an end of the shaft, the clotengagement element and the shaft being configured for deployment in ablood vessel; and a stabilizer configured to at least partially surroundthe shaft and to maintain a portion of the shaft in a non-contactingrelationship with the blood vessel wall.

In FIG. 2, for example, shaft 116 is maintained in non-contactingrelationship with the vessel wall through control shaft 114's centralinterconnection to capture element 104. Thus, when shaft 116 enters thelumen defined by capture element 104, it is biased in a direction towardthe center of the vessel. This in turn helps to maintain the engagementelement in manner that when rotated, tends to rotate in the longitudinaldirection of the vessel rather than substantially transverse to thelongitudinal direction. This is just one example of a stabilizerstructure. Any structure that holds an engaging element's shaft awayfrom a vessel wall is also contemplated to be encompassed by thisembodiment.

Control shaft 114 may also be configured to transition clot captureelement 104 from the expanded configuration to an at least partiallycontracted configuration. For example, movement of control shaft 114 inthe direction shown by arrow 115 in FIG. 2 may result in an appliedforce to proximal end 104 a of clot engagement element 104. The appliedforce to proximal end 104 a of clot capture element 104 may also be inthe direction shown by arrow 115, which may thereby result incontraction of clot capture element 104.

During retraction, clot capture element 104 may contract, exertingforces 1016, 1018 (FIG. 8) on clot 1000 and/or clot engagement element102 when clot 1000 and/or clot engagement element 102 are within centrallumen 110 of clot capture element. Forces 1016, 1018 may maintain clot1000 within central lumen 110 of clot capture element 104 during removalof clot 1000 from a blood vessel 1002 and may mitigate a tendency ofclot 1000 to break into multiple pieces. The clot may then be retrievedfrom the vessel with the clot retained solely within the capture elementand engagement element, as illustrated in FIGS. 7A and 7B.Alternatively, for clots small enough to fit within sheath 118, the clotcan be pulled into the sheath 118 before removal from the vessel, asillustrated in FIGS. 7C and 7D. In this manner, the sheath 118 mightexert further holding force on the clot.

In accordance with at least some embodiments, a sheath may be provided,surrounding and compressing the capture element and the engagementelement. The sheath may be removable to thereby enable the captureelement to expand in a blood vessel in which the sheath is deployed, andto enable the engagement element to expand within the capture element. Asheath may be any structure that is capable of retaining one or more ofa clot engaging element and a clot capture element, while being capableof sufficiently flexing in order to deploy one or more of those elementsin a vessel.

Consistent with at least some exemplary embodiments of the disclosure,an exemplary sheath 118 is illustrated in FIG. 1. Clot engagementelement 102 and clot capture element 104 may be delivered to a clot sitewithin the sheath 118. Sheath 118 may be a hollow tubular structurehaving a central lumen configured to surround clot engagement element102 and clot capture element 104 (FIG. 1A). Sheath 118 may further beconfigured to protect clot engagement element 102 and clot captureelement 104 as they follow a delivery path to the clot site.Accordingly, sheath 118 may be made of any suitable biocompatiblematerial and have any suitable shape and/or configuration so long assheath 118 may be configured to traverse a patient's vasculature whilemaintaining clot engagement element 102 and clot capture element 104 intheir respective contracted configurations upon delivery to and removalfrom a clot site. Further, upon removal of clot engagement element 102and clot capture element 104 from the clot site, sheath may beconfigured to maintain a clot within its central lumen as well (FIG.7D).

Additionally, sheath 118 may be configured to allow for controlledexpansion of clot capture element 104 and clot engagement element 102.For example, as previously discussed, clot capture element 104 and clotengagement element 102 may be configured to expand upon removal ofsheath 118. Sheath 118 may be retracted in a direction away from distalend 104 b of clot capture element 104. Accordingly, sheath 118 may beremoved at a rate that may control the rate of expansion of clot captureelement 104 and clot engagement. Further, sheath 118 may be retracted adistance that may control the amount of clot capture element 104 andclot engagement element 102 that may be exposed and expanded (FIG. 1B).Alternatively, the sheath 118 may be help substantially stationary, andthe clot capture element 104 and clot engagement element 102 may beadvanced, resulting in expansion of those elements.

In accordance with another embodiment of the disclosure there may beprovided a tubular clot capture element having a first internaldiameter, and a clot engaging element having a second external diameter,wherein the first diameter and the second diameter are selected topermit the clot engaging element to be rotated within the tubular clotcapture element.

By way of example only, and as illustrated in FIG. 2 as well as theother figures, the inner diameter of clot capture element 104 issufficiently sized so that clot engaging element 102 is able to berotated therein. Depending on the ultimate commercial design, this mayprovide the operator with the freedom to encircle a clot with anengaging element 102 at the same time that the clot is being drawn intothe capture element 104. Or it may provide the operator with the abilityto turn the clot once it is within the capture element 104. As such, theelements 102, 104 may be sized such that an outer surface area of theclot engaging element 102 may contact an inner surface area of the clotcapture element 104.

During operation of clot removal device 100, a device operator may findit useful to prevent movement of clot engagement element 102 relative toclot capture element 104. This may be desirable, for example, duringdelivery of clot removal device 100 to the clot site and/or duringremoval of clot 1000 from a patient. Accordingly, FIG. 5 illustrates alocking mechanism 150 that may be used with clot removal device 100 forselectively locking shaft 116 of clot engagement element 102 in a fixedposition with respect to control shaft 114 of clot capture element 104.When locking mechanism 150 is rotated in one direction locking mayoccur, and when rotated in an opposite direction, release may occur.Locking mechanism may be any suitable device that selectively preventsrelative movement between the clot engagement element and the clotcapture element. Examples of locking mechanisms may include, but are notlimited to, snap locks, rotational locks, and interference fits. Forexample, in one embodiment, locking mechanism may be a torquer 150. Asimilar or differing locking mechanism may be used to control relativemovement between sheath 118 and capture element 104.

Clot removal device 100 may also include a component that may allow adevice operator to know the location of clot removal device 100 as ittravels to the clot site. Location components may include, but are notlimited to, radiopaque markers, sensors, and/or imaging devices. In oneembodiment, for example, distal end 104 b of clot capture element 104may include a radiopaque marker (not shown).

Turning now to FIGS. 6A-6B, 7A-7D, and 8, a procedure of removing a clotfrom a blood vessel is illustrated using clot removal device 100 shownin FIG. 1A. Clot removal device 100 may be delivered to a clot sitewithin a blood vessel 1002. Delivery of clot removal device 100 mayinclude transporting sheath 118, which may substantially surround clotengagement element 102 and clot capture element 104, within a patient'svasculature to a location proximate a clot 1000. A device operator mayinsert clot removal device 100 over a guidewire 120 in order to assureclot removal device 100 follows a correct path to the clot site. Duringdelivery within sheath 118, clot engagement element 102 may besubstantially surrounded by clot capture element 104, as illustrated inFIG. 1A. Alternatively, clot engagement element 102 may be locatedoutside of clot capture element 104, and may be pulled into clot captureelement 102 after grasping clot 1000 during a later point in theprocedure.

As previously discussed, a device operator may monitor the location ofclot removal device 100 as it approaches the clot site via sensors,radiopaque markers, and/or imaging devices. Once clot removal device 100has reached the clot site, the device operator may remove guidewire 120from clot removal device 100. The device operator may retract the sheath118 (or advance the engagement element) sufficiently so that theengagement element 102 can rotate. Alternatively, the sheath 118 may beremoved in its entirety. Upon diassociation of the sheath 118 from clotengagement element 102, clot engagement element 102 may then expandradially and be movable (e.g., longitudinal and rotational movement)within clot capture element 104. Both the clot engaging element 102 andthe clot capture element 104 may be self-expanding in a spring-likemanner. Clot capture element 104 may expand to the approximate size ofthe inner diameter of blood vessel 1002. As previously discussed, theexpansion of clot capture element 104 may initiate separation of clot1000 from blood vessel wall 1004.

The device operator may move shaft 116 of clot engagement element 102 inthe direction of arrow 1010 towards clot 1000 and rotate shaft 116 inthe direction of arrow 1012 which may cause clot engagement element 102to engage with clot 1000. Longitudinal movement of shaft 116 may causelongitudinal movement of clot engagement element 102 in the direction ofarrow 1010′, and rotational movement of shaft 116 may cause rotationalmovement of clot engagement element 102 in the direction of arrow 1012′.Clot engagement element 102 may be moved along a longitudinal axis 1006of blood vessel towards clot 1000. Upon a distal-most end of clotengaging element 102 reaching clot 1000, simultaneous longitudinal arotational movement of shaft 116 may cause clot engagement element 102to encircle clot 1000. If windings 108 of clot capture element 102 havea substantially constant pitch and a substantially constant radius, thenas the capture element 102 is wound, the windings will follow a singlepath, minimizing trauma to the clot, and thereby minimizing risk thatthe clot will break apart. As clot engagement element 102 encircles clot1000, clot engagement element 102 may be between clot 1000 and clotcapture element. In some instance of use, rotation of clot engagementelement 102 might result in an Archimedes screw effect, drawing the clotfurther into the engagement element 102 without the need tosignificantly advance the engagement element. The extent of theArchimedes effect, and whether it occurs at all, may vary depending onthe specific nature of the clot and the extent of its connection to thevessel wall 1004.

Encircling of clot 1000 by clot engagement element 102 may causeadditional expansion of clot engagement element 102. As previouslydiscussed, radially expansion of clot engagement element 102 may causean outer surface of clot engagement element 102 to exert a force on awall 1004 of blood vessel 1002, which may further aid in separating clot1000 from blood vessel wall 1004. The separation may aid in reducing theforce needed to remove clot 1000 from blood vessel 1002. The separationmay also aid in mitigating the tendency of clot 1000 to break intomultiple pieces during removal of the clot from blood vessel 1002.

The device operator may encircle clot 1000 with clot engagement devicesuch that the device operator may be capable of pulling clot engagementelement 102 and clot 1000, together, into clot capture element 104.Accordingly, the device operator may move shaft 116 in the direction ofarrow 1014 such that clot 1000 encircled by clot engagement element 102may be pulled through opening 112 and into central lumen 110 of clotcapture element 104.

As the device operator pulls clot 1000 and clot engagement element 102into central lumen 110 of clot capture element 104 in the direction ofarrow 1014, the device operator may also pull control shaft 114 of clotcapture element 104 in the direction of arrow 115. This pulling mayresult in clot capture element 104 applying radially contracting forces1016 and a longitudinal shearing force 1018 to clot 1000 and clotengagement element 102. These applied forces may aid the device operatorin maintaining clot 1000 within clot capture element 104 and removingclot 1000 from blood vessel 1002 without breaking clot 1000 intomultiple pieces. And if the clot does break, capture element 104 mayprotect against pieces becoming loose in the bloodstream.

As illustrated in FIG. 7D, the simultaneous pulling of clot captureelement 104 and clot 1000 encircled by clot engagement element 102 mayresult in the aforementioned components being drawn back into sheath 118in the direction of arrow 1020. The drawing of clot engagement element102 and clot capture element 104 back into sheath 118, may result in thetransition of clot engagement element 102 and clot capture element 104from the expanded configuration (FIG. 7C) to the contractedconfiguration (FIG. 7D). The device operator may then remove clotremoval device 100 from the patient's vasculature along longitudinalaxis 1006 of blood vessel 1002.

Alternatively, the clot may be removed from the vasculature withoutpulling the capture element and the engaging element back into thesheath. Instead, as the clot may be trapped within the capture element,the radial forces exerted upon retraction may be sufficient to compressthe clot within the capture element such that the structure may beretracted in a substantially expanded form.

The device operator may alter the method of removing clot 1000 fromblood vessel 1002 as necessary. For example, prior to positioning clotengagement element 102 for encircling of clot 1000, the device operatormay insert instrumentation through central lumen of clot capture element104 which may be necessary for cleaning out the clot site. Additionally,removal of clot 1000 may be accompanied by suitable tools for graspingand/or maintaining clot 1000 within clot capture element 104. Forexample, the device operator may employ a suctioning device at aproximal end of clot removal device 100. The suctioning device mayfurther aid in pulling clot 1000 into clot capture element 104 andretaining clot 104 within clot capture element 104 as clot 1000 is drawnout of the patient's vasculature.

In accordance with another embodiment of the disclosure, a method ofremoving a clot from a blood vessel may include deploying a tubular clotcapture element in a blood vessel, the clot capture element having anopening therein that receives and guides a clot engaging element,surrounding a clot with the clot capture element, and retracting theclot capture element in a longitudinal direction of the blood vessel,such that the clot capture element radially contracts, exerting aradially inward compression force on the clot. This embodiment of thedisclosure may be practiced with any of the clot capture elementsdescribed above, including, clot capture element 104.

In accordance with yet another embodiment of the disclosure, a method ofremoving a clot from a blood vessel may include delivering a tubularclot capture element having a first diameter to a clot site anddelivering a clot engaging element having a second external diameter tothe clot site, wherein the first diameter and the second diameter areselected to such that the clot engaging element rotates within thetubular clot capture element. As describe earlier in connection withFIG. 2, such a method may be accomplished, for example, when clotcapture element 104 is delivered to a clot site, clot engaging element102 is delivered to a clot site, and when the two elements' diameterspermit the engaging element to be rotated within the capture element.

While the capture element and the engaging element may be deployedtogether, such as in the same sheath, the disclosure in its broadestsense does not necessarily so require. The engaging element may, forexample, be delivered first, and the capture element may be subsequentlydelivered. Moreover, the engaging element when rotated may be sized tocontact the inner wall of the capture element, or the engaging elementmay be sized to avoid contact.

In accordance with a further embodiment of the disclosure, a method forremoving a clot from a blood vessel may include deploying a clotengagement element in a blood vessel, the clot engagement elementlocated on an end of a shaft; and at least partially surrounding theshaft with a stabilizer to maintain a portion of the shaft in anon-contacting relationship with the blood vessel wall. This method maybe practiced with or without a clot capture element, such as structure104, and without regard to any specific stabilizing structure. As waspreviously noted, depending on design choice, some embodiments of thedisclosure may benefit from a rotation of the engagement element 102when the engagement element is centered in the vessel. This may minimizethe pressure exerted on the vessel walls, while maximizing movement ofthe engagement element 102 in the longitudinal direction of the vesselto surround the clot. By stabilizing, toward the center of the vessel,the shaft (e.g., shaft 116) that rotates the engagement element (e.g.,102), longitudinal motion may be maximized. Thus, stabilization mayoccur by surrounding shaft 116 with any structure that generallymaintains it near the center of the vessel at locations proximate theintersection of shaft 116 and windings 108.

Other embodiments of the disclosure will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the disclosure being indicated by the following claims.

What is claimed is:
 1. A clot removal device, comprising: a tubular clotcapture element having a first internal diameter; and a clot engagingelement having a second external diameter, wherein the first diameterand the second diameter are selected to permit the clot engaging elementto be rotated within the tubular clot capture element.
 2. The device ofclaim 1, wherein the tubular clot capture element includes a mesh-likestructure.
 3. The device of claim 1, wherein the clot engaging elementincludes a coil.
 4. The device of claim 1, wherein the tubular clotcapture element includes a mesh-like structure and the clot engagingelement includes a coil, and wherein the coil is configured to berotated about the exterior of a clot and the mesh-like structure isconfigured to contain the coil and the clot.
 5. The device of claim 1,wherein the first diameter and the second diameter are chosen such thatan outer surface area of the clot engaging element contacts an innersurface area of the clot capture element.
 6. The device of claim 1,further comprising a locking mechanism locking the clot engaging elementwithin the clot capture element.
 7. The device of claim 1, wherein thefirst diameter and the second diameter are selected to permit the clotengaging element to longitudinally move within clot capture element. 8.The device of claim 1, wherein the first diameter and the seconddiameter are selected to permit the clot engaging element to expandwithin the clot capture element.
 9. The device of claim 1, furthercomprising a first shaft that extends from a proximal end of clotcapture element, and a second shaft extends from a proximal end of clotengaging element, and wherein the second shaft is configured to rotatewithin the first shaft.
 10. A method of removing a clot from a bloodvessel comprising the steps of: delivering a tubular clot captureelement having a first diameter to a clot site; delivering a clotengaging element having a second external diameter to the clot site,wherein the first diameter and the second diameter are selected to suchthat the clot engaging element rotates within the tubular clot captureelement.
 11. The method of claim 10, wherein the tubular clot captureelement includes a mesh-like structure.
 12. The method of claim 10,wherein the clot engaging element includes a coil.
 13. The method ofclaim 10, wherein the tubular clot capture element includes a mesh-likestructure and the clot engaging element includes a coil, and wherein themethod further includes rotating the coil rotated about the exterior ofa clot and containing at least a portion of the coil and the clot withinthe mesh-like structure.
 14. The method of claim 10, wherein the firstdiameter and the second diameter are chosen such that an outer surfacearea of the clot engaging element contacts an inner surface area of theclot capture element.
 15. The method of claim 10, wherein a lockingmechanism locks the clot engaging element within the clot captureelement.
 16. The method of claim 10, further comprising longitudinallymoving the clot engaging element within the clot capture element. 17.The method of claim 9, further comprising expanding the clot engagingelement within the clot capture element.
 16. The method of claim 9,wherein a first shaft extends from a proximal end of clot captureelement, and a second shaft extends from a proximal end of clot engagingelement, and wherein the method further comprises rotating the secondshaft within the first shaft.